a. Field of the Invention
This invention relates generally to communication networks, and more specifically to a system and method for transferring information among users communicating over a communication network.
b. Acronyms
The written description uses a large number of acronyms to refer to various services and system components. Although generally known, use of several of these acronyms is not strictly standardized in the art. For purposes of this discussion, acronyms therefore will be defined as follows:
ACM Address Complete ISUP Message
ADF Application Data Fieldxe2x80x94application layer for switch to DAP interface
ANM Answer ISUP Message
B-channel Bearer channel
BRI Basic Rate Interface
CA-TSC Call Associated Temporary Signaling Channel
CCITT Committee Consultif International Telephonique et Telegraphique
CIC Circuit Identification Code
CONN Connect ISUP Message
CPE Customer premises equipment
CPG Call Progress ISUP Message
D-channel Data channel
DAL Direct Access Line
DAP Data Access Point
DSS1 Digital Subscriber Signaling System No. 1
FAA Facility Accepted ISUP Message
FAR Facility Request ISUP Message
FRJ Facility Reject ISUP Message
FTP File Transfer Protocol
IAM Initial Address ISUP Message
IE Information Element
IMT Inter-Machine Trunk
ISDN Integrated Service Digital Network
ISUP ISDN User Part
MA UUI Message Associated User-to-User Information
NCA-TSC Non-Call Associated Temporary Signaling Connection
NSF Network-specific Facilities
OSID Originating Switch Identification
OTG Originating Trunk Group
PRI Primary Rate Interface
REL Release ISUP Message
REL COM Release Complete ISUP Message
RLC Release Complete ISUP Message
RNR Receiver Not Ready
RR Receiver Ready
SS7 Signaling System 7
NSGD Network-specific generic digits
TSID Terminating Switch Identification
TTG Terminating Trunk Group
USI User Service Information
UUI User-to-User Information
UUIE User-to-User Information Element
UUS User-to-User Signaling
c. Related Art
Prior to the introduction of the Integrated Services Digital Network, or ISDN, the traditional telephone system used the same channel for both signaling and for voice transmission. This method, in traditional telephone systems, is known as in-band signaling, where signaling information for a connection is sent along with the conversation over the same voice channel. This type of signaling occurred in three ways: prior to establishing the conversation path, following the termination of the conversation path, or during the existence of the conversation path. The time required to transition between signaling states and conversation states is essentially unproductive time for the circuit.
By moving the signaling out-of-band in the case of, for example, ISDN, the conversation path becomes more productive. In addition, the ISDN method of signaling in a datagram format is faster and thus ISDN systems can transfer more information. This is accomplished, at least in part, because ISDN typically has at least one single signaling channel for multiple conversation channels.
The ISDN has two transmission methods: primary rate interface (PRI) and basic rate interface (BRI). Primary rate interface typically carries twenty-three bearer channels and one signaling channel. It is possible to have more than twenty-three bearer channels per signaling channel with the limitations being traffic congestion on the signaling channel and limitations of the switching system. Also, there may be multiple signaling channels for a set of bearer channels to provide redundancy. An example of this is a 94B+2D system spanning 4 DS-1 interfaces of 24 channels each. In contrast, basic rate interface carries two bearer channels and a data channel.
User-to-user signaling service exists for users who subscribe to either the basic rate interface or the primary rate interface. With the primary rate interface, multiple voice channels can be served by at least one signaling channel.
The ISDN signaling channel is directed by an originating inter-exchange carrier switch to a first signal transfer point. The signaling channel is then transferred via a signaling network such as the SS7 network to a second signal transfer point. The signaling channel information is then transferred to a terminating inter-exchange carrier switch.
The present invention is directed toward a system and a method for allowing users of a communication network to exchange data via a connection path over the communication network. When a user wishes to transfer data such as user-to-user information to another user, the invention routes the information over either the voice network or the signaling network. As a result, this user-to-user information can be transferred concurrently with or without other network communication, for example, a telephone call. The invention allows for the efficient transfer of multiple data transfers between a pair of switches to occur over a pair of connection paths, one on the voice network and one on the signaling network.
During a typical communication across the network, the users communicate by transferring frames of data across the signaling network. These frames are, for example, ISDN frames or other groupings of data, and can include data such as voice data, modem data or other communication-related data in a voice portion of the block. In addition to this voice portion, one or more of these blocks of data can include a second portion referred to as a signaling portion. It is this signaling portion which contains the user-to-user information.
In accordance with a feature of the invention, it may be offered on a subscription basis at a switch to place functional requirements on signaling traffic, congestion control, billing, fraud management, network management, testing systems and other process within the communication network.
One aspect of the invention examines the signaling portion of the frame of data to determine whether it contains user-to-user information to be transferred from a first user to one or more other users. If there is user-to-user information to be transferred, this data is removed (copied or extracted) from the frame and optionally formatted. One type of formatting performed is packetizing the user-to-user information from one or more frames into one or more packets of user-to-user information. The user-to-user information is then transferred to the recipient via an overlay network.
Another aspect of the invention is congestion control strategy that addresses both network congestion and user congestion.
An object of this invention is to use a communications network more efficiently when transferring information over the signaling network for two different connections between two switches.
Another object of this invention is to allow a first person to communicate via voice with a second person and transmit data to the same or a third person.
A further object of this invention is to provide congestion control to prevent overburdening the communications network, particularly by one individual.
A further object of this invention is to have scalability for future demand and expansion.
An advantage of the invention is that users can transfer user-to-user information without conducting a typical network communication such as a phone call. The user-to-user information may be included in the signaling portion of the frame. Another aspect of the invention detects the user-to-user information, builds a separate block (for example, a packet) of user-to-user information and sends this block via the voice path to the other user.
Another advantage of this invention is the efficient use of a communications network between two switches by using a pair of voice and signaling paths for multiple connections between two switches.
Another advantage of this invention is the ability to handle congestion at the switches or the user""s equipment.
Another advantage of this invention is the novel database for maintaining information on the status of connections with other switches from a particular switch.
Another advantage of this invention is the ability to handle multiple connection requests between two switches where the requested connections include temporary signaling connections.
A further advantage of this invention is the mapping of communication messages from messages transmitted from a person to a switch to messages to be transmitted between switches.
Further features and advantages of the present invention, as well as the structure and operation of various embodiments of the present invention, are described in detail below with reference to the accompanying drawings.